The present invention relates generally to the field of consumer electronics, and in particular relates to power adapters.
Many consumer products and other electrical devices employ power adapters for the purpose of converting a power input received from a power source into a power output suitable for use with the internal circuitry of the device. For instance, an AC adapter converts AC power input provided by an electrical receptacle into a DC power output. External AC power adapters provide several design advantages over AC power adapters that are internal to a device.
In certain instances, regulations require components that can be energized with AC power to be disposed in a secure housing so as to protect against inadvertent user contact with the energized component. In addition, a device can be made smaller and lighter when the size and weight of the AC power adapter, along with its housing or other safety features, are located outside of the device.
Conventional external AC power adapters have a “brick” configuration and can include a housing that contains power circuitry operable to receive AC power, convert the AC power to DC power, and output the DC power to the device. Such adapters are typically placed on the floor out of sight, for instance behind or under furniture, and are therefore often located in uncontrolled and unobserved environments.
In order to isolate the energized components from children, pets, and others who may unknowingly attempt to access such components, conventional AC adapters have housings that have no ventilation provided, thereby preventing inadvertent access to the interior components. Unfortunately, all power supplies, and therefore all external AC power adapters, generate some amount of interior heat.
An external AC power adapter having a sealed housing does not provide an efficient means for dissipating internal heat, thereby limiting the amount of power that can be economically delivered to a device without overheating the adapter. For example, plastic is usually the material used to construct an adapter housing due to its properties as a strong, low-cost electrical insulator having a favorable heat-rise allowance as dictated by applicable government agency standards. The sealed housing, however, causes the interior heat-generating components to diffuse their heat load through the housing into still air. Because plastic is a poor thermal conductor, and because still air results in poor thermal transfer, a conventional external AC power adapter is severely limited in the amount of power it can supply for a given adapter.
Accordingly, it has become desirable to provide external adapters having air ventilation capabilities. However, openings in the adapter housing that provide for air inputs and outlets also render the adapters susceptible to liquid ingress due to spills, splashes, and the like.